Underwater drilling derrick



Dec. 8, 1953 G. R. HOPKINS 2,661,600

UNDERWATER DRILLING DERRICK Filed Dec. 51, 1947 2 Sheeis-Sheet 1 Dec. 8, 1953 G. R. HOPKINS 2,661,600

UNDERWATER DRILLING DERRICK Filed D80. 31, 1947 2 Sheets-Sheet 2 Patented Dec. 8, 1953 STATS UNDERWATER DRILLING DERRIGK:

Georgelt. Hopkins, Silver Spring, Md.

Application December 31, 1947, Serial No. 795,105

is filaims. i

This invention relates to a method of drilling for oil or gas in water ranging in depth from about 20 feet to 190 feet, and possibly deeper.

It is unnecessary to explain why this invention is pertinent at this time as the potentialities of the underwater reserves on the continental shelf and elsewhere are even now much appreciated. The development of such reserves awaits mainly a safe and economic method of reaching such deposits. With demand outdistancing domestic supply, it is vital that this country find more oil and quickly.

Among the objects of the invention, severally and interdependently, are to provide a novel method and means for facilitating underwater drilling, a simple and economical arrangement for assisting such work, and novel features, ele-- ments and combinations contributing to the realization of the foregoing objects. The invention resides in the new combinations of steps and in the new structural elements and combinations hereinafter described and particularly pointed out in the appended claims.

In the accompanying drawings forming a part of this specification:

Fig. l is a more or less diagrammatic elevational perspective, partially broken away, of one embodiment of the invention.

Fig. 2 is an elevation partly in section, showone mode of constructing a downwardly fiaring concrete foundation employing a sinkable form with demountable casings communicating therewith.

Fig. 3 is an elevation of the downwardly flaring concrete foundation with the shell removed.

Fig. l is a horizontal section of Fig. 2 taken at the level of the tops of elements 28, and

Figs. 5, 5 and 7 are, respectively a plan view of the top end of the member 22 of Fig. '1, and horizontal sections through the structure of Fig. 1 tel-zen just above the derrick floor 23, and just below the cellar floor thereunder.

There is nothing complicated about this in vention, in fact, its simplicity would seem to be one of its strongest attributes. In the form shown in Fig. l, the structure comprises-a downwardly flaring concrete, or concrete filled foundation element t, and a compartmented structure having a centrally apertured downwardly flaring bottom formed to fit over and embrace the downwardly flaring foundation element l, the compartmented structure having a, fioata tion and ballasting compartment surrounding said foundation element with further compartments thereabove. This compartmented structure, like a bottle, when partially empty, is floatable and is sometimes referred to herein, for brevity, as the bottle. In the preferred form shown it iscompletely covered on the outside with a welded shell about one quarter of an inch thick. This shell also covers the upper, or derrick floor 2:3, and the lower, or cellar floor therebelow. Thus the bottle has three separate water-tight compartments designated as i, '2, and 3 in Fig. 1. Number I points to the main derrick space above the derrick floor, 2 to the space between the two floors, and 3 to the generally annular space below the lower floor and between the concrete pyramid embracing and outer walls. The bottle in Fig. 1, being drawn on a scale of a fraction of an inch to the foot, may be, say, 30 feet wide at the base, 90 feet tall, and standing in water 75 feet deep at high tide. Greater depths could be reached by adding welded sections to the top of the neck.

The bottle is supported in a vertical position in four ways: First, by resting on'a truncated octagonal pyramid of concrete, designated as :3 in Fig. 1; second, by friction from being inserted through the seafloor. The insertion in Fig. 1 happens to be about 5 feet; presumably it would be greater in a muddy bottom or in shallow water (to provide overhead clearance), but might be less in sandy terrain. Third, by resting on a layer of mud forced down under pressure be" tween the bottom of the concrete pyramid and the sea floor, and fourth, by 5 or 6 guy wires, one of which is designated 5 in Fig. 1. Each guy wire enters through a horizontal slit at the top of the bottle and travels down to a strong spring ii in Fig. 1, within reach of the upper floor.

Because of the factors of time, depth, and weather hazards. it might be desirable to construct the concrete pyramid in advance, that is, before the arrival of the bottle. This has been provided for by the creation 01- a foundation laying assembly, shown in elevation as Fi 2.

Essentially, the foundation layer consists of a casing about i-feetin diameter, 7 in Fig. 2, surrounding a casing about 2 feet in diameter, 8 in Fig. 2, screwed into a metal-covered base in the shape of a truncated octagonal pyramid, the 2-foot casing. extending through this base. The

structure is. tall enough to reach from the sea fioor'to a safe distance above the surface. Jpward and downward movements. on the location are'controlled by pumping mud (or water) or air into the central casing through-openings 9 and H). Once in a vertical position with the aid of suitable guy wires and levels, and with the sides imbedded in the sea floor, the water inside the pyramid is pumped out by electric pump ll through hoses l2 and I3. Concrete is then poured into the top to fill the space up to M, the top of the base. The two casings are then unscrewed jointly at 15 and I and raised to the surface by pontoons.

Fig. 3 is an elevation of the concrete pyramid with the shell removed. It shows the portion of the inner 2-foot casing which is left imbedded in the concrete. It also shows as IS a portion of a 2-inch pipe utilized to convey mud under pros sure to the contact between the concrete andthe underlying sea floor, which contact is designated as I l in Fig. 3. Designated as 58 is a recess extending around the pyramid. The sides of the recess help in preventing lateral movement, whereas its base serves as a footing for the drilling structure and a rest for a rubber seal. A few feet of this rubber seal or pad is designated as !9 in Fig. 1.

Fig. l is a sectional view of the base of the shell of Fig. 2 cut through just above the bottom of the concrete. It shows 4 partitions dividing the'octagonal-shaped contact of the concrete and the sea floor into quadrants. The number 2% points to one of these partitions in Fig. 4 and to a side view of one in Fig. 2. Fig. 4 also shows the bottom ends of twelve 2-inch pipes, one of which was described above as IS in Fig. 3. The functions of the remaining eleven are described below. Number 2! points to the end of hose i2 left imbedded in the concrete.

Fig. 5 is a view looking down on the crown block of Fig. 1. It shows the ends of the eight vertical, or nearly vertical, supporting members (indicated by Ts) surrounded by the welded shell. This view also shows the two insulated tubes, one of which is designated as 22 in both Figs. 1 and 5, used for ventilation and escape in case of accident. They extend down the walls to just above the cellar floor, and are accessible to the upper or derrick floor, designated as 33 in Fig. 1.

Fig. 6 is a view looking down on the upper or derrick floor as though the bottle were cut through a few feet above the door. This view shows the square outline of the floor superimposed on the square outline of the larger, lower floor, The double lines at right angles in Fig. 6 indicate the suggested beam arrangement. Circular line 25 is the outline of the body of the bottle as it meets, and is welded to, the upper floor. The T at 25 indicates one of the vertical posts reaching downward to the lower floor. The T at 2% marks the base of one of the nearly ver tical supports already mentioned in describing Fig.5.

Fig. '7 is a View looking downwardly from a plane just below the lower floor. This floor is square like the upper floor, but the inside beam arrangement (omitted for clarity) varies so as to best support the underlying base. In Fig. '7 features of the base of the bottle are shown. Thus 2? is one of eight bottom edges of the metal shell surrounding the concrete pyramid, 28 is one of the slanting edges of the pyramid, 29 is one of eight slanting beams attached to the bottom of vertical post 39, which extends from the lower floor downward to the bottom of the pyramid. The outside shell of the base, having to withstand relatively more stress than the shell above, would presumably be thicker.

The general plan of operation is as follows: The bottle is constructed from the bottom up while floating in a vertical position. Heavy drilling equipment is placed on the two floors and covered with cellophane, or other protective material, before the outside shell is welded in place.

The bottle is towed to the location. Pontoons around the circumference would probably be'necessary at this stage.

If the foundation has been laid previously by the foundation laying assembly of Fig. 2, the bottle is lowered into place on top of the pyramid and into recess 18 by filling space 3 with mud,

space 2 with water, and as much of space i with water as is necessary. Once the bottom is imbedded in the sea floor sufficiently to stop seepage up the sides of the pyramid-with the help of rubber seal lthe water in spaces I and 2 may be pumped out.

If the foundation has not been laid previously, the sinking procedure is much the same as above except space i is completely filled with water to provide maximum weight. 'ter the guy wires are in place and the bottle has practical stability, the water is pumped out and concrete poured into the pyramidal space. Before the concrete is poured, a 2-foot pipe, already described as the lower end of 3 in Fig. 2, is placed in the center. Twelve pipes, one designated as is in Figs. 1, 2, 3 and 4, are also placed in the concrete. Eight of these pipes are for reinforcement and as receptacles for explosives to shatter the concrete into movable pieces if the well is dry. Th other four, as mentioned above, convey mud under pressure to just below the base of the concrete. Each pipe serves a quadrant separated by the four partitions. One of these partitions is designated as 23 in Figs. 2 and 4. A system of levels operating electric motors to pump mud to the quadrants provides an automatic method of keeping the bottle vertical at all times. Such a system of levels may consist of conventional water levels, such as the Parker water leve described at page 2740 of Knights Mechanical Dictionary (Ford & ('30., N. Y., N. Y. 1874) in which float chambers partly filled with liquid are connected together at their bottoms by a relatively long tube so that as the system is tilted the flow of liquid causes one of the floats to rise and another to fall. As above indicated this rise and fall of the floats may operate electric motors to control the pumping or mud as in conventional float controlled electric sump pumps, the mud being delivered by each such pump to the quadrant that will tend to restore the bottle to plumb, and hence to restore the floats to the positions at which the pumps will be cut off.

After stability is assured, all small items of equipment are lowered inside the bottle and drilling begins. The mud in space 3 is used as the drilling mud. Just how much equipment would be within the structure and how much on the attending craft would depend on the particular operation, hence will not be discussed here. Because of the lack of space in the neck of the bottle in which to store drill pipe, a collapsible bit inside of welded or flush-joint casing probably would be desirable.

In drilling on dry land speed i stressed, but in underwater drilling safety should be given first consideration. It is believed that with the help of breakwater action from attending craft or supplemental floating structures, the bottle will have sufiicient stability to withstand all but severe hurricanes, such as appear in som part of the Gulf of Mexico about once a year. These always g1ve several days warning, or at least time enough to raise the bottle to the surface, assisted by loontoons attached to rings, such as 3! in Fig. 1. and tow it to port or to a deep spot for sinking. If a freak storm should upset the bottle and break the casing, the bottle would float to the surface. If a ship should hit and crush the top, th men would slide their oxygen helmets into position and enter space 2 between the floors.

If production were found, the concrete pyramid would provide an excellent anchor for whatever surface connections would be required.

While exemplary embodiments of the several features of the invention are herein set forth they are of course to be considered as illustrative and not restrictive of the invention, the scope of which is defined in the appended claims.

I claim:

1. A structure for underwater drilling comprising a downwardly flaring concrete foundation element and a compartmented bottle-like structure having a centrally apertured downwardly flaring bottom formed to fit over and embrace said downwardly fiaring foundation element, said compartmented structure having a flotation and balancing compartment positioned to surround said foundation element and having further emptiable ballasting compartments thereabove, said emptiable ballasting compartments affording working space within said structure after positioning of said bottle-like structure on the sea floor in embracing relation to said concrete foundation element.

2. A structure according to claim 1 further comprising a sealing ring between said bottle bottom and said concrete foundation for preventing seepage of water inwardly through the central aperture of said bottom.

3. A structure according to claim 2 in which said foundation is provided intermediate its height with a reentrant peripheral belt affording a horizontal lodge, in which said bottle-bottom is formed with a complemental ledge, and in which said sealing ring lies between said ledges.

4. A structure according to claim 2 further comprising means sub-dividing the region underlying said concrete foundation and means for selectively pumping mud under pressure into the subdivisions of said region for keeping the bottlelike structure plumb.

5. A structure according to claim 4 in which the selective pumping of mud under pressure is automatically controlled by a system of levels responsive to the departure of the structure from plumb.

6. A structure according to claim 1 in which the concrete foundation has a casing element extending centrally therethrough, and in which the compartment of the bottle-like structure surrounding the foundaticn element is filled with drilling mud for Weighting the same at a low level and for circulation to a well drilling tool operable through said casing element.

7. A structure according to claim 1 in which the bottle-like structure is separable from the foundation element for removal from the site, and in which the flaring foundation and bottlebottom serve to guide reassembly of the bottle structure on the foundation element on its return to the site.

8. A structure according to claim 1 in which the downwardly flared foundation element is separate from the bottle structure, and in Which said flaring foundation element and said flaring bottle bottom serve to guide assembly of the bottle into embracing relation to said foundation element.

9. A method of constructing at a selected underwater site a structure for underwater drilling operations which comprises sinking into the bottom at the selected site a metal form of downwardly flaring shape having extending from its upper end two removable concentric casings, casting a concrete foundation in said form, removing said casings, and sinking into embracing relation to said form a prefabricated bottleshaped structure having a reentrant bottom complemental to said form.

10. A method according to claim 9 further comprising the steps of sub-dividing the region of penetration of the metal form into the bottom at the site, and installing within the form conduits leading to each such sub-division before casting the concrete foundation in the form, and after casting and setting of the concrete foundation in the form selectively pumping mud under pressure through said cast in conduits to plumb the structure as needed.

GEORGE R. HOPKINS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 560,088 Eells May 12, 1896 819,317 Shrewsbury May 1, 1906 868,092 Hennebique Oct. 15, 1907 1,868,494 Collins July 26, 1932 2,171,672 Plummer Sept. 5, 1939 FOREIGN PATENTS Number Country Date 338,106 Germany of 1921 60,410 Denmark of 1942 

